solar collector

ABSTRACT

A solar collector of the direct flow type comprises a solar absorbing tube  3  containing elongate tube  11,  and a working fluid. The elongate tube  11  contains a concentrically positioned inner pipe  12  thereby forming two concentric internal flow passage ways  13, 14  for the flow of a fluid to be heated. The elongate tube  11  extends out of one end of the solar absorbing tube  3  and into an end fitting  15  wherein an annular outer passageway  13  of the elongate tube  11  communicates with a cold fluid inlet conduit  16  within the end fitting  15  and the inner passageway  14  of the elongate tube  11  communicates with a hot water outlet conduit  17  within the end fitting  15.  A central dividing wall  19  divides the fitting  18  into the cold fluid inlet conduit  16  and the hot fluid outlet conduit  17.  The dividing wall  19  is a separate insert component which is mounted in the passageway. Fluid can flow between the tubular passages  18  of adjacent solar tubes  3.  The open ends of the passages  18  comprise recesses to provide a circumferential seat  20  for an o-ring  21  or similar sealing means to provide a fluid-tight seal when adjacent end fittings  15  are mounted together.

INTRODUCTION

The invention relates to a solar collector for converting solarradiation into heat and to transfer the latter with the maximum possibleefficiency to a fluid heat transferring means (e.g. water or air)whereby the heat can be utilised in a domestic or industrialapplication, for example to heat a domestic hot water or central heatingsystem.

A solar collector typically comprises a number of elongate tubescontaining a radiation absorbing plate for absorbing solar radiation incontact with a pipe through which the fluid to be heated can be passedor within which is contained a working fluid for transferring heat tothe fluid to be heated. The radiation absorbing plate and at least aportion of the pipe are enclosed within an evacuated radiationtransparent enclosure to prevent heat loss.

In one type of solar collector, known as the direct flow type, the fluidto be heated flows through the pipe in contact with the plate for directconduction of heat between the plate and the fluid.

In an alternative type of solar collector, known as the heat pipe type,the pipe forms a closed chamber and contains a working fluid, the pipedefining an evaporator section, in thermal contact with said radiationabsorbing plate, and a condenser section remote from said plate, saidplate and said evaporator section of said elongate tube being enclosedwithin the evacuated radiation transparent enclosure to prevent heatloss. The condenser section is placed in thermal contact with the fluidto be heated to allow heat transfer between the working fluid and thefluid to be heated.

The heat pipe type of collector utilises the phase change of the workingfluid to achieve greater efficiency. The energy which is required forthe flow of the working fluid is provided by gravity so that no externalpumping source is necessary. A known heat pipe type solar collector isdisclosed in GB2103350.

Both types of solar collector further comprise a heat collectionmanifold containing a fluid to be heated and having at least one solartube receiving aperture therein for insertion of on end of each elongatetube to enable the fluid to be heated to pass into and out of the pipeof each elongate tube, in the case of the direct flow type, or to permitheat transfer between the working fluid within the condenser section ofthe pipe and the fluid to be heated in the case of the heat pipe type.The manifold is typically provided with inlet and outlet connections.

The separate elongate tubes and the heat collection manifold of thesolar collector need to be capable of being readily assembled on siteand designed so that they are capable of taking up the tolerances whichare usual in this field of the technology without risk of damage orleakages. In addition, it is necessary that these component parts beeasily replaceable. Traditional solar collector manifold typically has afixed number of receiving apertures as shown in FIG. 1. A traditionalsolar collector 1 comprises a manifold housing 2, a plurality ofelongate tubes 3 and a support structure 4. The manifold is typicallyprovided with an inlet port 5 and an outlet port 6 to allow the flow ofthe fluid to be heated. A plurality of inlet apertures 7 is alsoprovided to allow the insertion of the elongate tubes 3 into themanifold 2. The restrictive design of such traditional solar thermalcollectors has limited the flexibility of the solar collector forvarious applications. Significant redesign of the heat collectionmanifold 2 is typically required in order to provide systems of variablesize and energy generating capability. Traditional manifolds are fixedin their dimensions and the number of solar tubes that they canaccommodate.

The present invention aims to address the limitations of currentcollector design by providing a solution that is sufficiently flexibleto allow a collector to be constructed with any number of solar tubesand the size of which is not limited to the design and construction ofthe manifold.

The benefits of such an approach mean that the collector can be moreaccurately sized for its specific application or to fit confined orunusual spaces.

An additional aim of the present invention is to provide a solarcollector having a high efficiency and which can be constructed cheaply,and can readily be assembled and overhauled, using less components thanprior art devices.

STATEMENTS OF INVENTION

According to the invention there is provided a modular solar collectorcomprising at least one elongate tube, said at least one elongate tubeincluding means for absorbing solar radiation, means for transferringheat from said heat absorbing means to a fluid to be heated and an endfitting providing fluid connection means for connecting with acorresponding end fitting of an adjacent elongate member to permitpassage of fluid between the end fittings without requiring a separatemanifold, the end fitting comprising a fluid passageway, the end fittingbeing adapted to sealingly engage a similar passageway of an adjacentend fitting, the passageway being divided by a longitudinally extendingdividing wall into a cold fluid passageway for a cold fluid stream and ahot fluid passageway for a hot fluid stream wherein the dividing wallcomprises a separate component which is mounted in the passageway.

In one embodiment the end fitting comprises mounting means for thedividing wall. The mounting means may comprise a mechanical mountingmeans.

In one case the mounting means comprises a receiver for reception of thedividing wall.

The receiver may comprise a longitudinal part which extendslongitudinally along the end fitting. The longitudinal part may comprisean elongate slot extending along at least a portion of the end fitting.In one case the receiver comprises a pair of appositely directedelongate slots. Such an arrangement facilitates ease of insertion of thedividing wall, on assembly, and provides a highly efficient mountingmeans.

In one embodiment the receiver comprises a transverse part which extendstransversely at least partially across the end fitting.

The transverse part may comprise a support which extends transverselyacross the end fitting. There may be a pair of supports which arespaced-apart to define transverse receiving slot therebetween. Such anarrangement facilitates ease of insertion and mounting of the dividingwall. The transverse part also provides enhanced stability.

The transverse part may be located at one end of the fitting.

In one case the end fitting is of a rigid plastics material and thedividing wall is also of a rigid plastic material.

In one embodiment the dividing wall comprises an opening through which ahot fluid pipe of the solar collector tube extends for delivery of hotfluid from the solar collector tube into the hot fluid passageway.

In one embodiment the dividing wall is removable from the fitting. Thisarrangement facilitates assembly/disassembly.

In one embodiment the solar collector has parallel hydraulic flow.

In one case the end fitting comprises a fluid passageway, the endfitting being adapted to sealingly engage a similar passageway of anadjacent end fitting.

Preferably the end fitting comprises a seal for sealing engaging thepassageways of adjacent end fittings. The end fitting may comprise agroove or recess for receiving an O-ring seal.

In one embodiment the end fitting comprises a receiving portion forreceiving an end of a fluid flow pipe of a solar collector tube or acondenser section of a solar collector tube. The receiving portion mayextend substantially orthogonally to the fluid passageway.

The invention also provides a solar collector assembly comprising aplurality of end fittings joined together, an end fitting at one end ofthe assembly comprises a first blocking means for blocking one of thepassageways and an end fitting at an opposite end of the assemblycomprises a second blocking means for blocking the other of thepassageways.

In one case the receiving section is adapted for sealingly engaging withan end of a fluid flow pipe or a condenser section of a solar collectortube.

The receiving section may comprise a smooth face for engaging a seal ora seal for sealing engaging with an end of a fluid flow pipe of a solarcollector tube. The seal may comprise an O-ring. The receiving sectionmay be adapted for sealing engagement with a sealing plug of a condensersection of a solar collector tube.

The cold fluid passageway is preferably in fluid communication with acold fluid pipe of the solar collector tube.

In a preferred embodiment, on assembly of one end fitting to an adjacentsimilar end fitting, the dividing walls of the end fittings aresubstantially contiguous.

The dividing wall facilitates the parallel flow of thermal fluid whenadjacent end fittings are engaged together.

In one embodiment the solar collector is provided with a cold fluidpassageway seal and a hot fluid passageway seal that engage at oppositeends of the collector array assembly to block the respectivepassageways.

In one embodiment the hydraulic flow of fluid is in parallel andsimultaneous through all solar collector tubes in a collector arrayassembly.

In one embodiment the solar collector comprises a protective casing forreceiving the end fitting and an end of the solar collector tube. Theend fitting and/or the end of the solar collector tube are preferablyreleasably engageable in the protective casing.

In one case the protective casing comprises a main protector body and aclosure part which is movably mounted to or removable from the mainprotector body. Preferably the protective casing comprises a hinged orpivotal lid part.

In one embodiment the protective enclosure has an end capping. The endcapping may comprise a first part and a second part which are movablerelative to one another from an open configuration (to receive an endfitting) to a closed configuration. The second part may be hingedelymounted to the first part for movement between the open and closedconfigurations.

In one embodiment the protective casing comprises a receiver forreceiving a locking clip for securely mounting the solar collector tubeand/or the associated end fitting in the protective housing.

The protective casing may comprise a support structure. The supportstructure may be integral with the protective housing.

In one case the support structures of adjacent protective casings areinterlinkable. Adjacent support structures may be interlocked by aninterlink component. At least part of the interlink component may beintegral with the support structure. The interlink component may beseparate or separable from the support structure.

The invention also provides a solar collector assembly comprising aplurality of similar solar collectors of the invention.

According to the invention there is provided a solar collectorcomprising at least one elongate tube, said at least one elongate tubeincluding means for absorbing solar radiation, means for transferringheat from said heat absorbing means to a fluid to be heated and fluidconnection means for connection with corresponding fluid connectionmeans of an adjacent elongate member and/or to an inlet or outletconduit to permit passage of said fluid to be heated between adjacentelongate members without requiring a separate manifold.

Preferably said connection means is provided at one or both ends of eachelongate member.

Preferably each elongate member includes connection means to enable theelongate member to be connected to a supporting structure.

Preferably each fluid connection means preferably includes one or moreseal means, such as an o-ring or a compression fitting.

Preferably said absorbing means of each elongate tube comprises aradiation absorbing surface, such as a plate, enclosed within anevacuated radiation transparent enclosure formed from a radiationtransparent material, such as glass.

Preferably the fluid connection means is formed on an end fittingprovided on one or both ends of the evacuated tube of each elongatetube. Preferably said supporting structure connecting means are providedon each end fitting. In one embodiment said supporting structureconnecting means comprises one or more channel sections arrangedtransverse to the longitudinal axis of each elongate tube.

In a preferred embodiment, the fluid connection means comprises atubular opening adapted to sealingly engage a similar tubular opening onan adjacent elongate tube. Preferably said tubular opening includes acentral dividing wall to divide said opening into an inlet and an outletport. An o-ring seal may be provided between the tubular openings ofadjacent elongate tubes to prevent fluid leakage.

In one embodiment, said radiation absorbing surface of each elongatemember is in thermal contact with an elongate tube having at least oneinternal flow passageway for the flow of said fluid to be heated, saidat least one internal flow passageway communicating with said fluidconnection means.

Preferably said elongate tube includes a first passageway extending froma fluid inlet to a distal end of the tube and a second fluid passagewayextending from said distal end to a fluid outlet adjacent to said fluidinlet. The first and second fluid passageways may be arrangedconcentrically or side by side, separated by an internal dividing wallwithin the elongate tube. Where the first and second fluid passagewaysare arranged concentrically, said first passageway, comprising an inletpassage, may be defined by an annular space between in and outerconcentrically arranged pipes, and said second passageway, comprising anoutlet passage, may be defined by the inner one of said concentricallyarranged pipes.

The fluid connection means may be arranged such that the plurality ofelongate tubes are connected in parallel, whereby a cold fluid inletcommunicates with an inlet end of the first passageway of each elongatetube and a heated fluid outlet communicates with an outlet end of thesecond passageway of each elongate tube.

Preferably said connection means of each elongate member is defined by atubular passage extending through said end fitting and being open onopposing sides of said end fitting to communicate with a correspondingpassage of adjacent elongate member, said tubular passage having acentral dividing wall dividing the passage into an inlet stream and anoutlet stream, said first passageway of the elongate tube communicatingwith said inlet stream and said second passageway communicating withsaid outlet stream. Alternatively, the inlet stream and outlet streammay be defined by separate substantially parallel passageways extendingthrough the end fitting.

In an alternative embodiment said radiation absorbing surface of eachelongate member is in thermal contact with an evaporator section of aheat pipe comprising an elongate tube containing a heat transfer medium,a second section of said elongate tube, defining a condenser section ofthe heat pipe, being in thermal contact with a fluid chamber definedwithin said elongate member, preferably within said end fitting, andcommunicating with said fluid connection means to enable heat transferbetween said fluid to be heated and said heat transfer medium.

In such embodiment, said fluid chamber of each elongate member may bedefined by a passage extending through said end fitting having anopening at either end thereof to define said fluid connection means forfluid communication with a corresponding fluid chamber of adjacentelongate members, the condenser section of the elongate tube passinginto or forming a wall portion of said fluid chamber to permit heattransfer between fluid within said chamber and a working fluid withinsaid condenser section.

The present invention combines a number of previously separatecomponents and therefore reduces the overall complexity of the solarcollector resulting in lower cost and material usage without anycompromise in the efficiency, ease of assembly and reliability of thesolar collector.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be described, byway of example only, with reference to the accompanying drawings, inwhich:—

FIG. 1 is a perspective view of a prior art solar collector;

FIG. 2 is a cross-section of a solar collector tube of the direct flowtype;

FIG. 3 is an exploded perspective view of an end fitting part of a solarcollector of the invention;

FIG. 4 is a perspective view of the assembled end fitting of FIG. 3;

FIG. 5 is a longitudinal cut-away view of the end fitting of FIG. 4;

FIG. 6 is another longitudinal cut-away view of the end fitting of FIG.4;

FIG. 7 is an exploded perspective view of part of the end fitting ofFIGS. 4 to 6;

FIG. 8 is a perspective view of the assembled end fitting part of FIG.7;

FIGS. 9 and 10 are perspective views of the part of FIGS. 3 to 8 with adirect-flow type tube and an end fitting;

FIG. 11 is a cut-away view of two connected solar tube and end fittingsfor the direct flow type of tube;

FIG. 12 is a cut-away view of a connected solar tube and end fitting forthe direct flow type of tube;

FIG. 13 is a planar cross-sectional view of the connected tube of thedirect flow type with the end fitting;

FIG. 14 is an isometric view of two of the end fittings and tubes in afirst embodiment of the connection technology;

FIG. 15 is a cut-away partially cross-sectional view of the end-fittingsand tubes of FIG. 14;

FIG. 16 is a cross section of the two end fittings and tubes of FIGS. 14and 15;

FIG. 17 is a perspective view of two adjacent end fittings connectedtogether with a resilient clip in place;

FIG. 18 is a perspective view of a single solar collector with a firstembodiment of an outer protective casing;

FIG. 19 is an exploded view of a detail of FIG. 18;

FIG. 20 is an exploded view of another detail of FIG. 18;

FIG. 21 is an enlarged view of the outer protective casing part of FIG.18;

FIGS. 22 to 26 are perspective views illustrating the assembly of a tubeand the protective casing of FIG. 18;

FIGS. 27 to 29 are further perspective views illustrating the assemblyof a tube and a protective casing;

FIG. 30 is a perspective view of a number of tubes with the connectiontechnology of the invention when combined together;

FIG. 31 is a plan view of a number of tubes connected together withprotective casings in place;

FIG. 32 is a cut-away view of two adjacent tubes connected together withprotective casings in place;

FIG. 33 is a cross sectional view of the assembly of FIG. 32;

FIG. 34 is a view similar to FIG. 31 showing the tubes disconnected fromeach other;

FIGS. 35 and 36 are perspective views of connected tubes with variousbrackets/mountings;

FIG. 37 is a cross sectional view of an assembly of several tubes andend fittings with end connectors in situ;

FIG. 38 is a schematic view illustrating fluid flow in the solarcollector;

FIG. 39 is a perspective partially exploded view of a solar collectorillustrating end fittings;

FIG. 40 is a perspective view of FIG. 39 assembled; and

FIGS. 41 to 44 are cross sectional views illustrating the assembly ofend fittings of the solar collector;

DETAILED DESCRIPTION

As illustrated in FIG. 2 to FIG. 44 a solar collector assembly of thedirect flow type comprises a solar absorbing tube 3 comprising anevacuated radiation transparent enclosure 8 enclosing an absorbingsection 9, comprising a radiation absorbing plate 10 for absorbing solarradiation and an elongate tube 11, containing a working fluid (heattransfer medium), in thermal contact with said radiation absorbing plate10. The elongate tube 11 contains a concentrically positioned inner pipe12 thereby forming two concentric internal flow passageways 13, 14 forthe flow of a fluid to be heated. The elongate tube 11 extends out ofone end of the solar absorbing tube 3 and into an end fitting 15 whereinan annular outer passageway 13 of the elongate tube 11 communicates witha cold fluid inlet conduit stream 16 within the end fitting 15 and theinner passageway 14 of the elongate tube 11 communicates with a hotfluid outlet conduit stream 17 within the end fitting 15. Fluid passesfrom the annular outer passageway 13 to the inner passageway 14 via aflow path provided at a distal end of the elongate tube 11.

The end fitting 15 incorporates a tubular passage 18 having a centraldividing wall 19 dividing the passage 18 into said cold fluid inletconduit 16 and said hot fluid outlet conduit 17. The dividing wall 19 isprovided with an opening 24 through which the hot fluid pipe 14 of thesolar collector tube 3 extends for the delivery of hot fluid from thesolar collector into the hot fluid passageway 17. To facilitate themanufacturability of the components of the end fitting 15 the centraldividing wall 19 in this case is a removable component. The centraldividing wall 19 in combination with the opening 24 as assembled in theend fitting 15 allows for the parallel flow of fluid through a multitudeof solar collector tubes 3 that are adjacently connected to each other.

Referring to FIGS. 3 to 10 there is illustrated an end fittingcomprising a housing with a separate dividing wall insert 19. Thedividing wall insert 19 forms a dual chamber component that facilitatesparallel flow through all tubes in an assembled array. The separatedividing wall 19 facilitates ease of manufacture as the housing can bereadily moulded and the dividing wall 19 can subsequently be inserted.On assembly, the dividing wall insert 19 engages in slots and/or groovesin the end fitting to retain it in situ.

In this case the end fitting 15 comprises a mounting means for mountingthe dividing wall insert 19. The mounting means is a mechanical mountingmeans and comprises a longitudinal part which extends longitudinallyalong the end fitting. The longitudinal part comprises a pair ofoppositely directed slots/grooves 120 in the inner surface of the endfitting which receive shoulders 122 in the longitudinal edges 121 of thedividing wall insert 19. The dividing wall is a push fit in the grooves120.

The mounting means also comprises a transverse part which extendstransversely across the end fitting 15, in this case at one end of theend fitting 15. The transverse part in this case comprises a pair oftransverse support parts 125 which are spaced-apart to define atransverse receiving slot 126 therebetween. The slot 126 receives an end127 of the dividing wall 19 to locate and retain the dividing wall 19,providing added stability whilst ensuring that the dividing wall insert19 can be readily inserted and retained.

Because the dividing wall 19 is a separate component from the main bodyof the end fitting it can be manufactured separately thereby simplifyingmanufacturing. For example, the end fitting and separate dividing wallcan be moulded from a temperature resistant polymeric material.

FIGS. 11 and 14 to 16 illustrate the connection of two end fittings 15connected to two solar tubes 3 of the direct flow type.

The tubular passage 18 extends transversely across the end fitting 15and is open at each side of the end fitting whereby a fluid can flowbetween the tubular passages 18 of adjacent solar tubes 3. The open endsof the passages 18 comprise recesses to provide a circumferential seat20 for an O-ring 21 or similar sealing means to provide a fluid-tightseal when adjacent end fittings 15 are connected together.

Each tubular passage 18 is provided with a receiving portion 22extending orthogonally to the tubular passage 18 for receiving an end ofthe concentric elongated tube 11. One or more O-ring seals 23 arelocated within annular seats around the periphery of the pipe forproviding a seal between the end of the pipe 11 and the pipe receivingportion 22.

The inner pipe 12 of the concentric elongate tube 11 defining said innerpassageway 14 extends beyond the outer part to extend through anaperture 24 in the dividing wall 19 of the tubular passage 18 wherebythe annular outer passageway 13 of the double walled pipe communicateswith one side of the tubular passage 18, defining the cold fluid inletstream 16, and the inner passageway 14 communicates with the other sideof the tubular passage 18, defining the hot fluid outlet stream 17.

An end region of the outer wall of the double walled pipe 11 includes aflexible section 25 in the form of a corrugated or convoluted section oftube to provide a degree of flexibility to allow for slight misalignmentof the pipe and to absorb shocks or impacts.

The end fitting 15 may be formed from a temperature resistant polymericmaterial, possibly by injection moulding.

FIGS. 14 to 16 show the connection of two end-fittings 15 connected totwo solar tubes 3 of the direct flow type. The inlet flow channel 16 ofone of the end fittings 15 communicates with the inlet flow channel 16of the adjacent end fitting 15. In addition, the manner in which theoutlet flow channel 17 communicates with the outlet flow channel in theadjacent end fitting 15 is also shown. The flow is illustrated in FIG.16 in which the dotted line arrow indicates hot fluid flow and the fullline arrow indicates cold fluid flow. The flow is also illustrated inFIG. 38.

FIG. 17 illustrates one way for securing adjacent tubes 3 to one anotherduring the installation of a collector using the current invention. Aresilient clip 32 is located into two channels 33 on one side of the endfitting 15 that engage with a circumferential protrusion 34 on theopposite end of an adjacent end fitting 15 to provide a secure lockingmechanism to withstand the high-pressure conditions that are normal inthis field. Various other connection technologies that may be utilisedinclude a twist lock fitting where an inclusion on one end-fitting 15engages with an inclusion on an adjacent end fitting, or a clamp thatengages with circumferential inclusions or protrusions on opposite facesof adjacent end-fittings in order to secure the two end fittingstogether.

In one embodiment of the invention the end fitting 15 is encased in aprotective enclosure 26 as shown in FIGS. 18 to 34. In a firstembodiment of the protective enclosure 26 this consists of a main bodyenclosure 27 that has an integral support structure 28. Additionally theprotective enclosure is provided with a lid 101. A plurality of solarcollector tubes incorporating the end fitting 15 and the protectiveenclosure 26 of the present invention are shown in FIG. 30.

FIGS. 18 to 29 show by way of an example a schematic of a single tube ofa first embodiment of the invention. When assembled the direct flow typeand the heat pipe type will have the same external aesthetic appearance.The finished tube comprises an upper fitting 50, a solar tube 3 and alower fitting 51. Preferentially both upper fitting 50 and lower fitting51 are provided with channels 52 to allow for the attachment ofsupporting structures.

Referring in particular to FIGS. 21 to 29 it will be noted that in thiscase the end cap for housing the end fitting comprises a fixed receiverportion 100 into which the end fitting is inserted and a lid part 101which is hingedly mounted to the receiver portion 100. The lid part 101is opened to receive the end fitting and after assembly the lid part 101is closed to form a protective cover.

FIGS. 30 to 44 further show the assembly of a number of tubes using thepresent invention to construct a solar collector.

The end fitting 15 fits into a protective enclosure 26 that comprises; amain body enclosure 27 (that includes an integrated structure forsupporting the tube when installed), and a lid 101. A retaining clip 32is provided to secure the tube into the end enclosure 26.

A tube 3, end fitting 15, and protective enclosure 26 are assembled asfollows. The end fitting 15 is located into position in the main bodyenclosure 27. The fitting 15 is inserted with the tube receiving port 22facing upwards and sliding the end fitting 15 horizontally into positionin the main body enclosure 27. Once the end fitting 15 is in position itis rotated through ˜90 degrees until the tube receiving port 22 isfacing the tube 3. The end fitting 15 will preferentially clip/lock intoposition by this 90 degree rotation action during assembly in thefactory.

The tube is then inserted into the large open end of the main bodyenclosure 27 so that the flexible neck/condenser of the tube fits intothe end fitting 15. Once the tube is inserted it is secured in positionby the retaining clip 32. The retaining clip 32 engages with a disc thatis inserted into the convolutions of the flexible bellow either on adirect flow or heat pipe tube when it is inserted to hold it in place.Once the retaining clip 32 is secured in place the tube cannot beremoved from the main body enclosure 26 as the clip 32 is securedagainst an internal planar face of the main body enclosure therebystopping the tube being removed.

Once the tube is secured in position the lid 101 is closed. The lid 101can be opened so that should a tube 3 need to be removed at a laterstage the lid 101 can pivot to an open position, thereby allowing accessto the retaining clip 32 (so that is can be disengaged/removed) to allowthe tube 3 to be removed from the main body enclosure 26.

FIG. 18 shows how the finished tube would leave the factory. O-rings 21would also be fitted in the grooves of 31 (see FIG. 13). It is also anoption to ship tubes 3 pre-assembled in groups of 2 or more (ideally 5or more).

FIGS. 34 to 35 show how the tubes may be connected together duringinstallation as follows:

FIG. 35 shows how the tubes can be twist-locked together making use ofprotrusions/inclusions on the end-fitting 15. A twisting through approx.20 degrees may be used to lock the tubes together.

FIG. 36 shows tubes when locked into position on a rail support 65.

FIG. 30 shows a multitude of tubes connected together—the product couldleave the factory pre-assembled as shown in FIG. 30 or as individualtubes that are assembled on-site in this manner by the installer.

Tubes can be connected together in any quantity of 2 or more. FIG. 34show a plurality of tubes before they are connected together and FIG. 31shows the same tubes after they are connected.

Referring to FIGS. 37 to 44 there is illustrated an assembly of solarcollector tubes with grommets 110, 111 and end fittings 112, 113. Thefittings 112, 113 are typically of brass for connection withconventional piping. The grommets 110, 111 which are typically of asuitable rubber or plastics are used to ensure that there is only oneflow channel in and one flow channel out from the solar collectorassembly.

In addition to being modular in construction the solar collector of theinvention provides hydraulic flow paths that facilitate a parallel flowof thermal fluid throughout the assembled collector array. The solarcollector of the invention can be constructed with any number of solartubes in series. The invention provides a parallel flow path through alltubes regardless of the size of the collector array and the size ofwhich is not limited to the size, design and construction of themanifold. The schematic of FIG. 35 shows one embodiment of a modularcollector that facilitates parallel flow by the hydraulic design of theflow paths and the insertion of flow channel plugs at each extremity ofthe collector array.

Various modifications and variations to the described embodiments of theinventions will be apparent to those skilled in the art withoutdeparting from the scope of the invention as defined in the appendedclaims. Although the invention has been described in connection withspecific preferred embodiments, it should be understood that theinvention as claimed should not be unduly limited to such specificembodiments.

1. A solar collector comprising at least one elongate tube, said atleast one elongate tube including means for absorbing solar radiation,means for transferring heat from said heat absorbing means to a fluid tobe heated and an end fitting providing fluid connection means forconnection with a corresponding end fitting of an adjacent elongatemember to permit passage of fluid between the end fittings withoutrequiring a separate manifold, the end fitting comprising a fluidpassageway, the end fitting being adapted to sealingly engage a similarpassageway of an adjacent end fitting, the passageway being divided by alongitudinally extending dividing wall into a cold fluid passageway fora cold fluid stream and a hot fluid passageway for a hot fluid streamwherein the dividing wall comprises a separate component which ismounted in the passageway.
 2. The solar collector as claimed in claim 1wherein the end fitting comprises mounting means for the dividing wall.3. The solar collector as claimed in claim 2 wherein the mounting meanscomprises a mechanical mounting means.
 4. The solar collector as claimedin claim 2 wherein the mounting means comprises a receiver for receptionof the dividing wall.
 5. The solar collector as claimed in claim 4wherein the receiver comprises a longitudinal part which extendslongitudinally along the end fitting.
 6. The solar collector as claimedin claim 5 wherein the longitudinal part comprises an elongate slotextending along at least a portion of the end fitting.
 7. The solarcollector as claimed in claim 6 wherein the receiver comprises a pair ofappositely directed elongate slots.
 8. The solar collector as claimed inclaim 4 wherein the receiver comprises a transverse part which extendstransversely at least partially across the end fitting.
 9. The solarcollector as claimed in claim 8 wherein the transverse part comprises asupport which extends transversely across the end fitting.
 10. The solarcollector as claimed in claim 9 wherein the transverse part comprises apair of supports which are spaced-apart to define a transverse receivingslot therebetween.
 11. The solar collector as claimed in claim 8 whereinthe transverse part is located at one end of the fitting.
 12. The solarcollector as claimed in claim 1 wherein the end fitting is of a rigidplastics material and the dividing wall is also of a rigid plasticmaterial.
 13. The solar collector as claimed in claim 1 wherein thedividing wall comprises an opening through which a hot fluid pipe of thesolar collector tube extends for delivery of hot fluid from the solarcollector tube into the hot fluid passageway.
 14. The solar collector asclaimed in claim 1 wherein the dividing wall is removable from thefitting.
 15. (canceled)
 16. The solar collector assembly comprising aplurality of similar solar collectors as claimed in claim 1 wherein anend fitting at one end of the assembly comprises a first blocking meansfor blocking one of the passageways and an end fitting at an oppositeend of the assembly comprises a second blocking means for blocking theother of the passageways.
 17. (canceled)
 18. (canceled)